KLRD1 and Behcet disease: These diverse HLA-B associations in HLA-B*51-negative German and Turkish patients as well as previous experimental hints for an involvement of NK cells in the pathogenesis of BD raised the question, could HLA as a ligand of NK cell receptors, in particular HLA-Bw4 as a public determinant of HLA-B locus antigens, play a role in genetic susceptibility to BD?